RU1837300C - Device for interface between user and communication channel - Google Patents

Description

 The invention relates to computer technology and can be used in systems for exchanging information between a computer and a remote external device.

The purpose of the invention is to increase the reliability of information transmission under the influence of impulse noise.

Figure 1 shows the functional diagram of the device; figure 2 is a timing diagram illustrating the operation.

A device for connecting a subscriber with a communication channel, contains a series-connected clock generator 1, a shift register 2, a switch 3 and amplifiers 4, an isolation unit 5 made on a transformer to the communication channel 6, an AND-NOT 7 element, trigger 8 , element NAND 9.

an AND-NOT element 10, a trigger 11, an AND-NOT element 12 or an element 13, an EXCLUSIVE OR element 14, a trigger 15, a trigger 16, an EXCLUSIVE OR element 17, a trigger 18, and a trigger 19.

Figure 2 shows the voltage 20 at the output of the transformer 5, voltage 21 at the output of the clock generator 1, voltage 22 at the output of trigger 15, voltage 23 at the output of trigger 16, short pulse interference 24.

The device operates as follows.

At the initial moment, the shift register 2 and the triggers 15,16,18,19 are reset to zero on the Reset bus. After that, pulses from the output of the generator 1 clock pulses at bit 00

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the demo of shift register 2 advances the level of the logical unit coming from the inverse input D. When filling in the shift register 2, the level of the logical unit goes to the input D of register 2, and it starts moving along the digits of the level of logic zero. Thus, signals are generated that enter the communication channel . The address input of the switch 3 receives the input information signal. Depending on its level (0/1), the signal generated by register 2 is fed to the corresponding output of switch 3 and through amplifiers 4 and transformer 5 to communication channel b.

The received signal from the communication channel through the transformer 5 is fed to the inputs of the AND-NOT elements 7, 9, 10, 12. Triggers 8, 11 are initially reset. The pulse corresponding to the positive half-cycle arrives at the second input of the AND-NOT 7 element and sets the trigger 8. In this case, the AND-NOT 10 element is closed and the AND-NOT element is opened 9. The pulse corresponding to

negative half-cycle, through

elements NAND 9 and OR 13 are fed to the sync output of the device. The trailing edge of the same pulse resets trigger 8.

However, short impulse noise entering the input of the device leads to false triggering of triggers 8, 11, i.e., errors in receiving information. A modulo 2 summation allows only single errors to be detected.

To eliminate this drawback, that is, to increase the fidelity of transmission, the signal 20 from the output of the transformer 5 is fed to the input of the EXCLUSIVE OR 14 element, the other input of which receives the signal 23 from the output of the trigger 16. If these signals are different, then a logic level is generated at the output of the element 14 units and the nearest leading edge of the pulses 21 from the output of the generator 1 sets the trigger 15, the output of which the level of the logical unit 22 is fed to the inputs I, K of the trigger 16. On the next front of the pulses 21 the trigger 16 tipping and repeats a state signal from the output transformer 5. Simultaneously, the signal 23 output from the flip-flop 16 to the input element 14, a logic level zero output which resets the flip-flop 15.

If the signal 20 from the output of the transformer is struck by short impulse noise 24, then a trigger 15 is installed on the leading edge of the closest impulse blocking the noise 15. However, at the end of the interference, the signal at the output

0

5

0

5 0 5 0

5

The ment 14 receives a logic zero level and resets the trigger 15. However, the trigger 16 does not change its state. Similarly, the effect of short pulsed interference on the signal from the other output of the transformer 5 is eliminated with the use of an EXCLUSIVE OR element 17 and triggers 18, 19.

Thanks to the above processing of the signals from the outputs of the transformer 5, the influence of short pulsed interference on the operation of trigger 8 is eliminated. errors caused by said interference are eliminated.

The advantage of the proposed device in comparison with the known ones is that the effect of short pulsed noise is eliminated, which significantly increases the accuracy of information transmission. Depending on the intensity of the pulsed noise and the requirements on the probability of error, the fidelity of transmission when using the claimed device increases by 2-5 times.

Claims (1)

SUMMARY OF THE INVENTION A device for connecting a subscriber to a communication channel comprising a clock, a shift register, a switch, two amplifiers, four NAND elements, two triggers, two XOR elements and a discharge unit, the output of the clock being connected to the shift register synchronization input, the first and second bit outputs of which are connected to the corresponding information inputs of the switch, the first and second outputs of which through the first and second amplifiers are connected through the block communication with the same outputs of the device for connecting to the inputs of the communication channel, characterized in that, in order to increase the reliability of information transmission in the presence of interference, it contains the fifth, sixth, seventh and eighth triggers and an OR element, and the output of the clock generator is connected to trigger synchronization inputs from the first to the fourth inclusive, the output of the first trigger is connected to the information input of the second trigger, the output of which is connected to the first inputs of the first and second NAND elements and the first element EXCLUSIVE YUSCHEE OR, whose output is connected to data input and an inverted reset input of the first flip-flop, the switch address inputs are inputs of the device for connection to the subscriber, the outputs of the first and second amplifiers are connected to a second input nepboro of the element EXCLUSIVE OR and with the first input of the second element EXCLUSIVE OR, respectively, the output of the second element of the EXCLUSIVE OR is connected to the information input and the inverse reset input of the third trigger, the output of which is connected to the information input of the fourth trigger, the output of which is connected to the second OR, the first inputs of the third and fourth elements And-h E. the output of the first element AND is NOT connected JH with the inverse input of the installation of the fifth trigger, the inverse output of which is connected to the second Odom third AND-NO element whose output is connected with an inverted L input for setting the sixth flip-flop, 0 5 whose direct output is connected to the device error output and to the second input of the second AND-NOT element. the output of which is connected to the reset input of the sixth trigger and the first input of the OR element, the output of which is the output of the device for connecting to the subscriber input, the inverse output of the sixth trigger is connected to the second input of the first AND-NOT element, the direct output of the fifth trigger is connected to the second input of the fourth element AND NOT. the output of which is connected to the second input of the OR element and the reset input of the shift register of the fifth and sixth triggers, the second bit output of the shift register is connected to the inverse information input of the shift register. (pc / & 1 go LMLLSHISHALL. I I jII  n li p Riga g. II I